Named for the capital of the German state of Brandenburg. Besides Berlin, Potsdam was the residence of Brandenburgian Electors and Prussian kings (Friedrich the Great, Friedrich Wilhelm I). Several famous castles, e.g. Sanssouci and the New Palace are located there. After World War II the Potsdam Conference took place at the Cecilienhof Palace. The Astrophysikalisches Observatorium Potsdam, devoted to the introduction and development of new research methods in astrophysics, was founded in 1874 at the Telegrafenberg. The well-known Einstein Tower for solar studies was erected by the architect Erich Mendelsohn in 1922. (M 23542) _ _.